1. Field of the Invention
The present invention relates to a method for producing an antireflection film, an antireflection film, and a coating composition. More specifically, the present invention relates to a coating composition which is capable of forming a multilayer structure in a single coating step and has high production efficiency, a method for producing an antireflection film having a multilayer structure with two or more layers using the coating composition, and an antireflection film produced by the method.
2. Description of the Related Art
An antireflection film is arranged on the surface of a display and required to have a low reflectance in order to prevent decrease in the contrast due to reflection of external light or reflection of an image in image display devices such as a liquid crystal display apparatus (LCD), a cathode ray tube display apparatus (CRT), a plasma display panel (PDP), and an electroluminescence display (ELD). In addition, it is also required to have high physical strength (scratch resistance and the like), transparency, and the like.
Accordingly, in the antireflection film, a functional layer such as a hard coat layer or a high refractive index layer, and a low refractive index layer with an appropriate film thickness, having a lower refractive index than a base material, are generally formed on the base material in this order.
Although this antireflection film is usually produced by a coating method, lamination of a plurality of thin films having different refractive indices has a problem in productivity in that the process should include a film-forming step starting with at least plural coating steps; it is essential to provide equipment required for the plurality of film-forming steps; and a process time for operating the equipment is also required.
In addition, the antireflection film is required to have further improvement in terms of adhesion properties between the respective layers and the scratch resistance of the surface.
With regard to such productivity, there has been proposed a technology for forming two or more layers from one coating liquid (see, for example, JP2006-206832A, JP2007-038199A, JP2007-238897A, and JP2009-198748A).